System and method for a multi-layer network element

A network element for forwarding packet on a network, the network element comprising:

• (a) at least one input port for receiving a packet;
• (b) processing logic for examining the packet and determining a first search key and a second search key associated with a first protocol layer and a second protocol layer, respectively;
• (c) a memory adapted to have at least a portion of its contents searched simultaneously and output a result based on a search;
• (d) first search circuitry configured to search the memory using the first search key and causing the memory to output a first search result;
• (e) second search circuitry configured to search the memory using the second search key and causing the memory to output a second search result;
• (f) at least one output port;
• (g) merge circuitry coupled to the memory, the merge circuitry configured to forward the packet to appropriate output ports, if any, of the at least one output port based on the first search result and the second search result.

A network element for forwarding packets on a network, the network element comprising:

• (a) at least one input port configured to receive a packet;
• (b) header processing logic configured to examine packet header information for determining a first search key and a second search key associated with a first protocol layer and a second protocol layer, respectively;
• (c) a memory;
• (d) first search logic coupled to the memory, the first search logic configured to cause the memory to output a first search result based on the first search key;
• (e) second search logic coupled to the memory, the second search logic configured to cause the memory to output a second search result based on the second search key;
• (f) at least one output port;
• (g) merge logic, coupled to the memory, configured to forward the packet to appropriate output ports, if any, of the at least one output port based on the first search result and the second search result.

A network element for forwarding packets on a network, the network element comprising:

• (a) at least one input port configured to receive a packet;
• (b) processing logic configured to determine first packet information and second packet information from packet header information associated with a first protocol layer and a second protocol layer, respectively;
• (c) a memory;
• (d) memory access logic coupled to the memory, the memory access logic configured to access the memory using a first address determined as a function of the first packet information to produce a first result and a second address determined as a function of the second packet information to produce a second result;
• (e) at least one output port;
• and
• (f) merge logic coupled to the memory, the merge logic configured to forward the packet to an appropriate output port of the at least one output port based on the first result and the second result.

An apparatus for making a forwarding decision for a packet entering a network element having at least one input port and at least one output port, wherein the packet enters the network element on an input port and exits the network element on appropriate output ports, the apparatus comprising:

• header logic configured to output, based on header information in the packet, a first search key associated with a first protocol layer, a second search key associated with a second protocol layer, and a default result;
• a memory configured to output a first forwarding result in response to receiving the first search key from the header logic, and to output a second forwarding result in response to receiving the second search key;
• merge logic configured to output information about appropriate output ports in response to the default result, the first forwarding result, and the second forwarding result;
• and
• forwarding logic configured to direct the packet from the input port to the appropriate output ports based on the information about the appropriate output ports.

A method of forwarding packets comprising the steps of:

• receiving a packet from a network at an input port;
• generating a first forwarding decision based upon information in a data link layer of the packet;
• generating a second forwarding decision based upon information in a network layer of the packet;
• determining a resulting forwarding decision based upon the first forwarding decision and the second forwarding decision;
• and
• forwarding the packet to one or more output ports identified by the resulting forwarding decision.